The Shimela-1 well in the South Omo Block onshore Ethiopia was drilled to test a prospect in a northwestern sub-basin of the vast Chew Bahir basin. The frontier wildcat well encountered lacustrine and volcanic rocks, including almost 100 m of net sandstone reservoir within siltstones and claystones, Tullow Oil announced. Trace thermogenic gas shows were recorded at 1,900 m.

The Exalo 205 rig drilled Shimela-1 to a final depth of 1,940 m. The rig will now be moved to drill the Gardim-1 wildcat exploration well in a completely separate sub-basin, in the southeastern corner of the Chew Bahir basin.

“Although the Shimela well only found traces of thermogenic gas, it has provided key data to continue to build our understanding of the northwestern part of the Chew Bahir basin. The prospectivity at the Gardim-1 well, which is targeting an independent petroleum system in a separate southeastern sub-basin, is not affected by this result,” Angus McCoss, Exploration Director for Tullow Oil, said.

Tullow operates the South Omo Block with 50% equity and is partnered with Africa Oil Corp (30%) and Marathon Oil Ethiopia Ltd (20%).